Experimental Determination of the Voltage Lead Error in an AC Josephson Voltage Standard

The National Research Council (NRC) of Canada has recently established an alternating-current Josephson voltage standard (ACJVS) system based on the National Institute of Standards and Technology pulse-driven Josephson junction arrays. This paper describes the efforts undertaken at the NRC and the experience that was gained. An experimental method of measuring corrections for the voltage probe lead errors is described, and first results are reported. By introducing the ACJVS, the NRC will be able to reduce the uncertainties of the thermal transfer standard calibration by threefold on the 200-mV range and five-to tenfold on the 20-mV range, in comparison with thermal-converter-and micropotentiometer-based calibrations.